Wing-chun, a determined young woman who runs a humble tofu shop in a remote mountain village with her father, sister, and aunt, hides a fierce secret: after she was nearly forced into an arranged marriage in her youth, she dedicated herself to mastering kung fu. Her sharpened skills help her stand up to predatory men who crave her beauty, but they also push away many suitors, much to her father's dismay. She becomes the village’s lone protector, taking on the local bandits who threaten the peace.
In the shadows of this tension, the two notorious bandit brothers—nicknamed the “Flying Chimpanzee” and the “Flying Monkey”—torment the village, preying on the vulnerable. The first to rise against them is Wing-chun herself, and she earns a fierce rival in Flying Monkey, a handsome widow named Charmy Catherine Hung Yan. Wing-chun rescues Charmy and gives her a job in the family shop, which only fuels the jealousy and danger surrounding Charmy’s presence and the predatory eyes of Flying Monkey. The sense of danger deepens as Wing-chun’s courage threatens to expose the bandits’ grip on the valley.
Wing-chun’s childhood sweetheart Pok-to Donnie Yen returns from years of training to win her hand, believing he can claim the woman he once loved. He arrives to find Charmy, who he initially assumes is Wing-chun, and he’s disappointed to discover that the Wing-chun before him is a tomboyish warrior rather than the traditional fiancée he imagined. Wing-chun stays quiet about this misunderstanding, choosing to protect her evolving identity and the path she’s chosen as a fighter.
A pivotal night explodes in violence when Wing-chun injures Flying Monkey in a duel, using a fireball that leaves him incapacitated and permanently unable to act on his predatory desires. This betrayal of expectations awakens Flying Chimpanzee, the elder brother, who vows vengeance. He kidnaps Charmy to draw Wing-chun and Pok-to into his fortress high in the mountains and traps them there. The terms of their fight are cruel: Wing-chun must pull a spear from a wall within three rounds, and if she fails, she will become Flying Chimpanzee’s prisoner. She fights with cunning and grit, managing to survive the challenge, yet she is not able to best the formidable foe outright, suffering injuries from Flying Chimpanzee’s fearsome “cotton belly.”
Seeking guidance, Wing-chun travels to consult her master, the abbess Ng Mui Cheng Pei-Pei, who represents the origin of her kung fu. Ng Mui counsels a stark choice: return to a normal life or continue the fight. This moment tests Wing-chun’s sense of duty and desire for a peaceful future. Meanwhile, Pok-to learns about Wing-chun’s braided, tomboy identity and the two finally acknowledge that love can coexist with strength. He reassures her that his feelings for her remain, regardless of appearance, and his acceptance becomes a turning point.
Armed with a new understanding of her own “inch strike,” Wing-chun discovers the key to defeating Flying Chimpanzee’s “cotton belly.” A serendipitous punch through a mosquito net—delivered by Pok-to’s instinctive action—unlocks this hidden power. With this revelation, she returns to the mountains to confront Flying Chimpanzee once more, translating skill, strategy, and courage into a decisive victory. The duel ends with Wing-chun’s triumph, compelling the bandits to bow to her superior prowess and authority.
With the threat neutralized, the village welcomes a restored sense of safety and unity. Wing-chun and Pok-to celebrate their union in a joyful wedding, surrounded by friends and family who recognize how far she has come—from a fearless fighter who stood up to oppression to a woman who can choose her own path and future. Their alliance marks a new era for the valley, where strength and tenderness coexist, and where love can flourish alongside power.
